<strong>Conductance biosensors based on DNA nanowires.</strong>

Molecular electronics devices are envisaged to supersede silicon-based ones in the future, in particular, due to their small size, biocompatibility and ability to self-assemble into larger functional units. Biosensors constitute one of the areas where those advantages would play a key role. Two new classes of synthetic DNA-nanowires are in particular promising for this application: triplexes consisting of one C-strand and two G-strands and pure guanine quadruplexes (four G-strands). Those molecules, while retaining DNA structural and recognition properties have enhanced mechanical rigidity, show promising signs of improved electrical conductivity. As was recently discovered within currently running EU Nanodevices project, those DNA nanowires can be intercalated with fluorescent porphyrin molecules. This intercalation changes both optical and electrical properties of the nanowires. To develop this concept further we will perform a simultaneous optical and AFM study of these molecules combined with electrical transport measurements. This would allow to match morphological changes observed upon intercalation optical and conductive properties on a single molecule level. This research will lay foundation to conductance biosensors based on DNA nanowires.